Physiological effects of polyphenols have recently attracted attention due to the increase in health consciousness and the demand for polyphenol-rich beverages has increased too. For example, catechin compound(s), which are a type of polyphenols, are known to have an inhibitory effect on increase in cholesterol and there are needs for beverages containing catechin compound(s). However, catechin compound(s) have a characteristic bitter taste and astringency and therefore methods for reducing the bitter taste and astringency have been proposed to make such beverages more drinkable. For example, Patent Literature 1 discloses that astringency characteristic of catechin compound(s) can be suppressed by adjusting the glutamic acid concentration in beverages containing catechin compound(s) within a certain range.